APATZINGÁN, Mexico — President Enrique Peña Nieto will welcome President Barack Obama and Canadian Prime Minister Stephen Harper to the industrial city of Toluca on Wednesday for a one-day summit designed to showcase North American trade ties and Mexico’s promising economic reforms.

But beleaguered businessman Carlos Halabe Ochoa says the instability in the nearby state of Michoacán should serve instead as a reminder of how Mexico’s security shortcomings continue to hijack the nation’s economic promise.

He said the regional economy had been thrown into chaos by greedy men who roam the area as if they own it, kidnapping business owners and demanding extortion payments and torching businesses that don’t comply. He compared the criminal presence to a tumor.

“The cancer was such that it overtook the entire community,” said Halabe, president of a local chamber of commerce known as Canaco. “It was hell.”

Experts say Michoacán is a microsm of the challenges faced by Mexico as Peña Nieto works to generate a new image for a country still grappling with issues of violence and lawlessness.

Both the United States and Mexico “have been working hard to change the narrative from security to the economy,” said Joy Olson, executive director of the Washington Office on Latin America. “But Michoacán is forcing security back on the agenda. It has to. Michoacán is hard to hide under the rug.”

A senior U.S. official said, “With respect to Michoacán, certainly we’re following closely what is happening there and stand by the government of Mexico as it confronts challenges there and elsewhere.”

The summit, marking the 20th anniversary of the landmark North American Free Trade Agreement, is aimed at rebooting NAFTA, in part by pushing for the Trans-Pacific Partnership, a potentially gigantic trade agreement being negotiated among 12 nations.

Leaders are expected to also discuss ways to make the flow of goods and people more seamless across the continent, similar to the European Union, something officials say they’re working toward with the help of technology. But they caution that in the U.S., a nation where border security remains a top issue, the road to more open borders is long.

For Obama, the visit is short, with less than 10 hours on Mexican soil. The Trans-Pacific Partnership faces strong opposition from labor, environmental and consumer groups, important constituents of his Democratic Party.

Other than trade and commerce, energy is expected to take center stage. In December, Mexico passed landmark energy reform. For the first time in 75 years, the country is opening to outside investors a sector that includes shale-gas deposits just across the border with Texas and deep-water oil production. Potential investors, some of them in North Texas, are awaiting more details.

But beneath the new emerging Mexico — with a thriving airplane industry in Querétaro state, transnational conglomerates in the northern city of Monterrey, and a string of auto assembly plants, including Chrysler in Toluca — is a bloodstain not easy to erase. Pockets of Mexico, including areas surrounding the site of the summit, are characterized by weak rule of law, which hinders prospects for investment.

On Sunday, headless bodies stuffed in trash bags were discovered near Nezahualcoyotl, just outside Mexico City. In the states of Coahuila and Tamaulipas, near the Texas border, dozens of human remains have been found in recent days, some unearthed from clandestine graves. Even regions traditionally known as safe havens display signs of concern. Police checkpoints guard the entrance to San Miguel de Allende, normally an idyllic haven for expats.

Then there’s Michoacán and the neighboring state of Guerrero, where civilian self-defense groups are taking the place of official authorities to protect residents. Last month, the Mexican government effectively legalized the self-defense movement after an agreement was reached with group leaders to incorporate the armed civilians into quasi-military rural defense groups.

“Michoacán is not Nuevo León,” said Jaime Rivera, a security expert at the University of Michoacán, referring to the northern industrial powerhouse state. “Michoacán is closer to Somalia, Liberia, Honduras.”

Apatzingán is a town of some 90,000 people and an agricultural market city and trade hub for mangoes, melons and grapefruit bound for the port city of Lázaro Cárdenas and beyond. Last month, the city appeared dead, with a vast number of stores closed on the orders of the Knights Templar cartel.

But in recent days, after the self-defense groups took control, there were traffic jams as commerce reopened. Lime growers held a meeting to set prices away from the influence of the Knights Templar, who used to undercut them by setting low prices.

“Maybe I can actually feed my family this year,” said Jesús Reyes, who was hauling limes picked in his 17 acres. “This may be a good year for us.”

But about 30 percent of shuttered businesses had not reopened, and another 30 percent were on the verge of collapse, Halabe said, adding that the new calm is riddled with uncertainty.

“We have no trust in state or local authorities,” he said.

A few blocks away, Gonzalo Zaragoza Mèndez sat in his tech store, which recently laid off his five workers due to declining sales. He said he was nervous after seeing his picture posted on a Facebook page of the Knights Templar, suggesting he was sympathetic to the self-defense groups. He has changed his routine and constantly watches his back, and is even pondering a move to Australia with his family.

Asked about the upcoming summit in Toluca, Zaragoza said: “I love my country. We have much to offer to the world, but all we ask for is basic protection, security. I hope the leaders hear our plea.”

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